Search Engine Optimization

I am using the responsive directory theme version 4.0. to create a directory of electricians in the United States.

I am using States as the categories.

This allows me to have pages like:

http://www.directory.com/listing-category/ ohio

as well as the specific listing page of an Ohio electrician:

http://www.directory.com/listing/allstar-electricians

My questions is how would I get / setup / enable web pages that would be for cities in Ohio?

Example:

http://www.directory.com/listing-category/ ohio/ cleveland that would than list all electricians in Cleveland, Ohio ?